When a compressed gas storage tank fails, the resultant explosion occurs so rapidly that the gas cloud can be considered adiabatic and assumed to not mix appreciably with the surrounding atmosphere. Consider the failure of a 2.5-m3 air storage tank initially at 15 bar. Atmospheric pressure is 1 bar, CP  7R/2. Provide an estimate by assuming reversibility.
a) Calculate the work done on the atmosphere. Does the reversibility approximation over-estimate or under-estimate the actual work?

b) A detonation of 1 kg of TNT releases about 4.5 MJ of work. Calculate the equivilent mass of TNT that performs the same work as in part (a).

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

An engine runs on the ideal diesel cycle. the cycle has a compression ratio of 20 and a cutoff ratio of 2. the highest temperature in the cycle is 1200 k. if the heat into the system is 300 kj/kg of working fluid and using variable specific heats determine the work produced per mass of working fluid